Review of Critical Care Medicine

Note:-Bolded or underlined statements are previous questions.

1.Attachments on the scapula:-No attachments for Pectoralis Major.

2.SITminor(Supraspinatus,Infraspinatus,Teres Minor inserted on gretaer tubercle of humerus on posterior side of top of humerus. All have attachments on scapula.Subscapularis inserted on Lesser tubercle of humerus.Pectoralis minor is inserted on coracoid process.

3.Tip of coracoid process:- Short Head of biceps and Coracobrachialis.

4.Carpal Bones :-

Proximal row:- ScaLunaTriqPisi (Scaphoid Lunate Triquetral Pisiform):Lateral to medial

Distal Row :- Trapezium,Trapezoid,Capitate and Hamate: Lateral to medial

The pisiform is a sesamoid bone in the tendon of flexor carpi ulnaris and articulates with the anterior surface of the triquetrum.

Most common site of scaphoid fracture is :
(A)Waist
(B)Proximal fragment
(C)Distal fragment
(D)Tilting of the lunate

Fractures of the scaphoid are the most common of carpal fractures. They usually occur in young adult men following falls on their outstretched palms. Experimental studies have shown that the force must be applied to the radial side of the palm, with the wrist extended a minimum of 95° (102). In that position, the scaphoid is the only carpal bone in contact with the radius. The proximal part of the scaphoid assumes a wedge-shaped configuration between the radius and capitate, where it is supported by the radial collateral and radiocapitate ligaments. The distal pole of the scaphoid, however, is unsupported and capsular structures in the area are lax. It is the distal pole that receives most of the applied force and the bone fractures at its most vulnerable area, its waist.

The profile of the bone is best seen on PA and posterior-oblique views with the wrist in ulnar deviation ( The posterior-oblique view visualizes the carpal bones on the radial side of the wrist, particularly the scaphoid, and the anterior-oblique view visualizes the pisiform and, to a lesser extent, the hamate)

Although radiographs taken immediately after the injury may be negative, the scaphoid should still be considered fractured until proven otherwise. Immobilize the wrist in a thumb spica splint or cast and repeat radiographs in 1 to 2 weeks. If there is a fracture, it should then be evident by the appearance of bone resorption at the fracture site. Occasionally, bone resorption does not appear until 3 weeks after the fracture, and even then radiographs may remain inconclusive. In these cases, radionuclide imaging with technetium-99m (99mTc) can be helpful (32). Although bone scans are highly sensitive and are generally positive within 24 h of a fracture, they are nonspecific. Therefore, although a fracture can be ruled out with a negative scan, a positive scan requires more specific imaging studies. Vibratory testing, using audible “intrasound” frequencies between 20 and 20,000 Hz (infrasound less than 20 Hz and ultrasound greater than 20,000 Hz are inaudible), has been shown to be effective in diagnosing occult scaphoid fractures (8). The test is considered positive when pain is sufficient to cause an immediate “positive retraction response.” The definitive test is a CT scan.

The second method of classification is based on the site of the fracture within the scaphoid, which is separated into proximal, middle, and distal thirds. Most fractures involve the middle third of the bone. They usually heal if they are not displaced, and there is no intercarpal instability.Q:- Fractures in the proximal third, sometimes referred to as the proximal pole of the scaphoid, have the highest incidence of nonunion and avascular necrosis because of the pattern of intraosseous circulation. The blood supply to the scaphoid enters dorsally and distally and traverses the bone in a proximal direction (36). Fractures in the distal third of the scaphoid are the rarest and tend to heal promptly because of the excellent blood supply in the area. Distal-third fractures include intraarticular fractures and fractures of the tubercle.

Q:-So non-union and delayed union is more common than malunion.

Avascular necrosis of the scaphoid (Priser’s disease) and of the lunate (Kienbock’s disease).

5.The anterior group of lymph nodes lie along the lateral thoracic vessels.Approximately 75% is via lymphatic vessels that drain laterally and superiorly into axillary nodes.

As indicated in Fig. 17-8, the lymph node groups are assigned levels according to their anatomic relationship to the pectoralis minor muscle(not pectoralis major). Lymph nodes located lateral to or below the lower border of the pectoralis minor muscle are referred to as level I lymph nodes, which include the axillary vein, external mammary(anterior axillary or pectoral group), and scapular groups. Lymph nodes located superficial or deep to the pectoralis minor muscle are referred to as level II lymph nodes, which include the central and interpectoral groups. Lymph nodes located medial to or above the upper border of the pectoralis minor muscle are referred to as level III lymph nodes, which consist of the subclavicular group. The plexus of lymph vessels in the breast arises in the interlobular connective tissue and in the walls of the lactiferous ducts and communicates with the subareolar plexus of lymph vessels. Efferent lymph vessels from the breast pass around the lateral edge of the pectoralis major muscle and pierce the clavipectoral fascia, ending in the external mammary (anterior, pectoral) group of lymph nodes. Some lymph vessels may travel directly to the subscapular (posterior, scapular) group of lymph nodes. From the upper part of the breast, a few lymph vessels pass directly to the subclavicular (apical) group of lymph nodes. The axillary lymph nodes usually receive >75% of the lymph drainage from the breast. The rest is derived primarily from the medial aspect of the breast, flows through the lymph vessels that accompany the perforating branches of the internal mammary artery, and enters the parasternal (internal mammary) group of lymph nodes

Axillary lymph node groups. Level I includes lymph nodes located lateral to the pectoralis minor muscle (PM); level II includes lymph nodes located deep to the PM; and level III includes lymph nodes located medial to the PM. Arrows indicate the direction of lymph flow. The axillary vein with its major tributaries and the supraclavicular lymph node group are also illustrated.

The boundaries for lymph drainage of the axilla are not well demarcated, and there is considerable variation in the position of the axillary lymph nodes. The six axillary lymph node groups recognized by surgeons (Figs. 17-7 and 17-8) are (a) the axillary vein group (lateral), which consists of four to six lymph nodes that lie medial or posterior to the vein and receive most of the lymph drainage from the upper extremity; (b) the external mammary group (anterior or pectoral group), which consists of five or six lymph nodes that lie along the lower border of the pectoralis minor muscle contiguous with the lateral thoracic vessels and receive most of the lymph drainage from the lateral aspect of the breast; (c) the scapular group (posterior or subscapular), which consists of five to seven lymph nodes that lie along the posterior wall of the axilla at the lateral border of the scapula contiguous with the subscapular vessels and receive lymph drainage principally from the lower posterior neck, the posterior trunk, and the posterior shoulder; (d) the central group, which consists of three or four sets of lymph nodes that are embedded in the fat of the axilla lying immediately posterior to the pectoralis minor muscle and receive lymph drainage both from the axillary vein, external mammary, and scapular groups of lymph nodes, and directly from the breast; (e) the subclavicular group (apical), which consists of six to twelve sets of lymph nodes that lie posterior and superior to the upper border of the pectoralis minor muscle and receive lymph drainage from all of the other groups of axillary lymph nodes; and (f) the interpectoral group (Rotter’s nodes), which consists of one to four lymph nodes that are interposed between the pectoralis major and pectoralis minor muscles and receive lymph drainage directly from the breast. The lymph fluid that passes through the interpectoral group of lymph nodes passes directly into the central and subclavicular groups.

6. Clavipectoral Fascia:-

Pierced by LTC

L-Lateral pectoral nerve

T-Thoracoacromial vessels

C—Cephalic VEIN

Clavipectoral fascia:-The clavipectoral fascia is a strong fibrous sheet behind the clavicular part of pectoralis major. It fills the gap between pectoralis minor and subclavius, and covers the axillary vessels and nerves. It splits around subclavius and is attached to the clavicle both anterior and posterior to the groove for subclavius. The posterior layer fuses with the deep cervical fascia which connects omohyoid to the clavicle and with the sheath of the axillary vessels. Medially it blends with the fascia over the first two intercostal spaces and is attached to the first rib, medial to subclavius. Laterally, it is thick and dense, and is attached to the coracoid process, blending with the coracoclavicular ligament. Between the first rib and coracoid process the fascia often thickens to form a band, the costocoracoid ligament. Below this the fascia becomes thin, splits around pectoralis minor and descends to blend with the axillary fascia and laterally with the fascia over the short head of biceps. The cephalic vein, thoraco-acromial artery and vein, and lateral pectoral nerve pass through the fascia.

7. Serratus Anterior muscle :- SERRATUS (AT = 8 Digitations from upper eight ribs)

Nerve supply:- C5,C6 and C7(long thoracic nerve)

Also called as Boxer`s muscle.-Along with the pectoralis minor the muscle pulls the scapula forwards around the chest wall to protract the upper limb(in pushing and punching movements)

Forms the Medial Wall of Axilla

Damage to the long thoracic nerve;-Because the long thoracic nerve passes down the lateral thoracic wall on the external surface of the serratus anterior muscle, just deep to skin and subcutaneous fascia, it is vulnerable to damage. Loss of function of this muscle causes the medial border, and particularly the inferior angle, of the scapula to elevate away from the thoracic wall, resulting in characteristic ‘winging’ of the scapula, on pushing forward with the arm.

True bout the Serratus anterior muscle is
A. Originates from the lower four ribs (upper 8 ribs)
B. Bipennate muscle (8 pinna)
C. Supplied by the subscapular nerve  (long thoracic nerve C5 C6 C7 roots)
D/ Helps in forced inspiration –True

Winging of scapula is due to paralysis of :
(A) Rhomboides (B) Trapezius
(C) L. dorsi (D) Serratus-anterior

8. Axilla:- The axillary inlet is oriented in the horizontal plane and is somewhat triangular in shape, with its apex directed laterally.The margins of the inlet are completely formed by bone.

• the medial margin is the lateral border of rib I;
• the anterior margin is the posterior surface of the clavicle;
• the posterior margin is the superior border of the scapula The apex of the triangularly shaped axillary inlet is lateral in position and is formed by the medial aspect of the coracoid process
• 

The anterior wall is formed by pectorales major and minor, the former covering the whole wall, the latter its intermediate part. The interval between the upper border of pectoralis minor and clavicle is occupied by the clavipectoral fascia. The posterior wall is formed by subscapularis above, and teres major and latissimus dorsi below. The medial ‘wall’ is convex laterally and is composed of the first four ribs and their associated intercostal muscles, together with the upper part of serratus anterior. The anterior and posterior walls converge laterally: the ‘wall’ is narrow and consists of the humeral intertuberous sulcus. The lateral angle lodges coracobrachialis and biceps.

So lateral wall is very narrow,its actually an angle.

Contents of Axilla:-

The axilla contains the axillary vessels, the infraclavicular part of the brachial plexus and its branches, lateral branches of some intercostal nerves, many lymph nodes and vessels, loose adipose areolar tissue and, in many instances, the ‘axillary tail’ of the breast. The axillary vessels and brachial plexus run from the apex to the base along the lateral wall, nearer to the anterior wall: the axillary vein is anteromedial to the artery. The obliquity of the upper ribs means that the neurovascular bundle, after it emerges from behind the clavicle, crosses the first intercostal space: its relations are therefore different at upper and lower levels. Thoracic branches of the axillary artery are in contact with the pectoral muscles; the lateral thoracic artery reaches the thoracic wall along the lateral margin of pectoralis minor. q:-Subscapular vessels descend on the posterior wall at the lower margin of subscapularis. The subscapular and thoracodorsal nerves cross the anterior surface of latissimus dorsi at different inclinations. Circumflex scapular vessels wind round the lateral border of the scapula; posterior circumflex humeral vessels and the axillary nerve curve back and laterally around the surgical neck of the humerus.

No large vessel lies on the medial ‘wall’, which is crossed proximally only by small branches of the superior thoracic artery. The long thoracic nerve descends on serratus anterior and the intercostobrachial nerve perforates the upper anterior part of this wall, crossing the axilla to its lateral ‘wall’

9.The Brachial Plexus:-Branches of the brachial plexus may be described as supraclavicular and infraclavicular

Dorsal Scapular nerve supplies rhomboids

Long thoracic nerve supplies the serratus anterior.

Point to note nerves from roots supplies the muscles inserted into the medial margin of Scapula.

The lateral pectoral nerve is larger than the medial, and may arise from the anterior divisions of the upper and middle trunks, or by a single root from the lateral cord. Its axons are from the fifth to seventh cervical rami. It crosses anterior to the axillary artery and vein, pierces the clavipectoral fascia and supplies the deep surface of pectoralis major. It sends a branch to the medial pectoral nerve, forming a loop in front of the first part of the axillary artery  to supply some fibres to pectoralis minor.

In a postfixed plexus the contribution by T1 is large,T2 is always present,C4 is absent and C5 is reduced in size.

In a prefixed plexus the contribution by C4 is large and that from T2 is absent,

Lower subscapular nerve supplies teres major

Upper and Lower subscapular Nerve supplies Subscapular muscles.

ROOT VALUES :-a) Musculocutaneous nerve:-C5,C6,C7 (Branches of lateral cord)

b)Ulnar Nerve :- C7C8T1 (Medial Cord)

c) Axillary nerve :- C5C6 (POST CORD)

D) Radial nerve (c5,c6,c7,c8,t1) Post Cord

10. Erbs Paralysis:- Upper Trunk C5,C6 injury   CAUSES Policemans tip or Porters Tip hand.Arm HANGS BY SIDE,IT IS ADDUCTED AND MEDIALLY ROTATED.Supination as well as flexion is lost ,so is abduction.

11.Klumpkes Paralysis/Neurogenic Thoracic Outlet Syndrome (arterial type is also discussed in addition due to anatomic relevance) :- Lower trunk (C8T1) injury causes Claw Hand due to unapposed action of long flexors and extensors of the fingers.In a claw hand there is hyperextension at the MCP joint and flexion at the IP joints.Horners syndrome is also seen in Klumpke`s paralysis.Klumpke`s paralysis is seen in Thoracic Outlet syndrome.Thoracic outlet is an anatomic region containing First Rib,Subclavian Artery and vein Brachial Plexus,The clavicle and Lung Apex.

At the superior thoracic aperture(Thoracic Outlet) , the superior aspects of the pleural cavities, which surround the lungs, lie on either side of the entrance to the mediastinum .Structures that pass between the upper limb and thorax pass over rib I and the superior part of the pleural cavity as they enter and leave the mediastinum. Structures that pass between the neck and head and the thorax pass more vertically through the superior thoracic aperture.

True neurogenic thoracic outlet syndrome (TOS) results from compression of the lower trunk of the brachial plexus or ventral rami of the C8 or T1 nerve roots by an anomalous band of tissue connecting an elongate transverse process at C7 with the first RIB.

Patients with neurogenic thoracic outlet compression may develop shoulder and arm pain, weakness, and paresthesias. Patients with arterial compression may experience claudication, Raynaud’s phenomenon, and even ischemic tissue loss and gangrene. Venous compression may cause thrombosis of the subclavian and axillary veins; this is often associated with effort and referred to as Paget-Schroetter syndrome.(New in 17th ed Harrison Page 1571)

Adson’s test is used to assess for the presence of Thoracic Outlet Syndrome at the scalene triangle. The patient is examined standing. The examiner palpates the radial pulse while moving the upper extremity in abduction, extension, and external rotation. The patient then is asked to rotate her head toward the involved side while taking a deep breath and holding it. A positive exam will result in a diminished or absent radial pulse.

Several maneuvers that support the diagnosis of thoracic outlet compression syndrome may be used to precipitate symptoms, cause a subclavian artery bruit, and diminish arm pulses. These include the abduction and external rotation test, in which the affected arm is abducted by 90° and the shoulder is externally rotated; the scalene maneuver (extension of the neck and rotation of the head to the side of the symptoms); the costoclavicular maneuver (posterior rotation of shoulders); and the hyperabduction maneuver (raising the arm 180°).Most patients can be managed conservatively. They should be advised to avoid the positions that cause symptoms. Many patients benefit from shoulder girdle exercises. Surgical procedures such as removal of the first rib or resection of the scalenus anticus muscle are necessary occasionally for relief of symptoms or treatment of ischemia.

12.  Trapezius (Accessory Nerve,XI):- Each trapezius muscle is flat and triangularly shaped, with the base of the triangle situated along the vertebral column (the muscle’s origin) and the apex pointing toward the tip of the shoulder (the muscle’s insertion)  The muscles on both sides together form a trapezoid.

The superior fibers of trapezius, from the skull and upper portion of the vertebral column descend to attach to the lateral third of the clavicle and to the acromion of the scapula. Contraction of these fibers elevates the scapula. In addition, the superior and inferior fibers work together to rotate the lateral aspect of the scapula upward to raise the upper limbs above the head.(Overhead abduction).

Motor innervation of trapezius is by the accessory nerve (XI), which descends from the neck onto the deep surface of the muscle . Proprioceptive fibers from trapezius pass in the branches of the cervical plexus and enter the spinal cord at spinal cord levels C3 and C4.

Acting with levator scapulae, the upper fibres elevate the scapula and with it the point of the shoulder; acting with serratus anterior, trapezius rotates the scapula forward so that the arm can be raised above the head; and acting with the rhomboids, it retracts the scapula, bracing back the shoulder. With the shoulder fixed, trapezius may bend the head and neck backwards and laterally. Trapezius, levator scapulae, rhomboids and serratus anterior combine in producing a variety of scapular rotations

Clinical anatomy: testing Trapezius is palpated while the shoulder is shrugged against resistance.

13.  Rhomboideus:-Retract the scapula Supplied by dorsal Scapular nerve.

14. Clavicle:- The shaft is gently curved and in shape resembles the italic letter f, being convex forwards in its medial two-thirds and concave forwards in its lateral third.

The clavicle begins to ossify before any other bone in the body, and is ossified from three centres. The shaft of the bone is ossified in condensed mesenchyme from two primary centres, medial and lateral, which appear between the fifth and sixth weeks of intrauterine life, and fuse about the forty-fifth day. Cartilage then develops at both ends of the clavicle. The medial cartilaginous mass contributes more to growth in length than does the lateral mass: the two centres of ossification meet between the middle and lateral thirds of the clavicle. A secondary centre for the sternal end appears in late teens, or even early twenties, usually 2 years earlier in females (Fig. 49.2). Fusion is probably rapid but reliable data are lacking. An acromial secondary centre sometimes develops at c.18 to 20 years, but this epiphysis is always small and rudimentary and rapidly joins the shaft.

The clavicle is often fractured, commonly by indirect forces, as a result of a violent impact to the hand or shoulder. The break is usually at the junction of the lateral and intermediate thirds, where the curvature changes, for this is the weakest part of the bone. A fracture medial to the conoid tubercle interrupts weight transmission from the arm to the axial skeleton. The resulting deformity is caused by the weight of the arm, which acts on the lateral fragment through the coracoclavicular ligament and draws it downwards. The medial fragment, as a rule, is a little displaced.

The coracoclavicular ligament connects the clavicle and the coracoid process of the scapula. Though separate from the acromioclavicular joint, it is a most efficient accessory ligament, and maintains the apposition of the clavicle to the acromion. Its trapezoid and conoid parts, usually separated by fat or, frequently, a bursa, connect the medial horizontal part of the coracoid process and lateral end of the subclavian groove of the clavicle; these adjacent areas may even be covered by cartilage to form a coracoclavicular joint.

The coracoclavicular ligament stabilizes the acromioclavicular joint. In acromioclavicular dislocation, the ligament is torn and the scapula falls away from the clavicle. Dislocation readily recurs because of the flatness and orientation of the joint surfaces.

15.

All of the following are branches of subclavian artery except :
(A)Vertebral artery
(B)Thyrocervical trunk
(C)Subscapular artery—-axillary artery branch
(D)Internal thoracic artery

16. Deltoid:-     ORIGIN                                                                              INSERTION                                                       NERVE                                                              ACTION

The two most superficial muscles of the shoulder are the trapezius and deltoid muscles (Fig. 7.34 and Table 7.1). Together, they provide the characteristic contour of the shoulder:

• trapezius attaches the scapula and clavicle to the trunk;
• deltoid attaches the scapula and clavicle to the humerus

Trapezius is attached to all structures except :
(A)First rib
(B)Clavicle
(C)Scapula
(D)Occiput