Bony Landmarks
Name the three bones that make up the shoulder complex?
Clavicle, scapula, humerus
Name the four rotator cuff muscles.
Supraspinatus, Infraspinatus, Teres minor, Subscapularis (SITS)
Name the five terminal branches of the brachial plexus.
Musculocutaneous, Axillary, Median, Radial, Ulnar
Name the joint where the clavicle attaches to the axial skeleton, and identify the structure inside this joint that divides it into two compartments.
Sternoclavicular (SC) joint; articular disc
A patient falls on an outstretched hand and now has a visible "step-off" deformity at the lateral clavicle. What injury do you suspect?
AC joint separation/sprain (accept distal clavicle fracture with sound reasoning)
This bony prominence on the lateral scapula articulates with the head of the humerus.
Glenoid cavity (glenoid fossa)
This muscle is the primary abductor of the shoulder from approximately 15° to 90° and has three distinct fiber regions.
Deltoid (anterior, middle, posterior fibers)
This nerve arises from the posterior cord and innervates the latissimus dorsi. Name the nerve and its root contributions.
Thoracodorsal nerve; C6, C7, C8
Name the two ligaments that connect the coracoid process of the scapula to the clavicle (together referred to as the CC ligament complex).
Conoid ligament and trapezoid ligament (together = coracoclavicular ligament)
A patient ruptures the long head of the biceps tendon. What is the classic visible sign, and where does this tendon originate?
"Popeye sign" (bunched-up muscle belly in the distal arm); originates from the supraglenoid tubercle of the scapula
Name the two tubercles of the proximal humerus and the structure that runs between them.
Greater tubercle, lesser tubercle; intertubercular (bicipital) groove — contains the long head of biceps tendon
Which rotator cuff muscle initiates shoulder abduction (first ~15°)? Which is the only internal rotator of the cuff?
Supraspinatus initiates abduction; Subscapularis is the only internal rotator of the cuff
Name the nerve that innervates the anterior compartment of the arm and its root contributions.
Musculocutaneous nerve; C5, C6, C7
This fibrocartilaginous rim deepens the glenoid cavity by approximately 50%, increases articular contact, and contributes to negative intra-articular pressure for stability. Name it and identify one common injury pattern associated with it.
Glenoid labrum; Bankart lesion (anteroinferior labral tear from anterior dislocation) — accept SLAP tear as well
A motorcyclist with forceful separation of the neck and shoulder presents with complete upper limb paralysis and anesthesia. What injury is this, and what is the most commonly cited percentage of brachial plexus injuries from this mechanism?
Brachial plexus injury (traction injury); approximately 83% from motorcycle accidents
A patient presents with pain at the "point of the shoulder." Name the joint and the two bones that form it.
Acromioclavicular (AC) joint — acromion of scapula + lateral clavicle
Name the three heads of the triceps brachii and identify which one crosses the shoulder joint.
Long head, lateral head, medial head; the long head crosses the shoulder joint (and helps resist inferior humeral dislocation)
Name the nerve innervating the triceps brachii, its root contributions, and one other muscle in the arm region it supplies.
Radial nerve; C5–T1; also innervates the anconeus
Name the three glenohumeral ligaments that reinforce the anterior joint capsule, and identify which one is the primary restraint to anterior translation at 90° of abduction.
Superior, middle, and inferior glenohumeral ligaments (SGHL, MGHL, IGHL); the inferior GHL (anterior band) is the primary restraint to anterior translation at 90° abduction
A patient presents with winging of the scapula when pushing against a wall. Name the injured nerve, its root contributions, and the muscle affected.
Long thoracic nerve; C5, C6, C7; serratus anterior
Name the three fossae associated with the scapula and what separates the upper two on the posterior surface.
Supraspinous fossa, infraspinous fossa, subscapular fossa (anterior); the spine of the scapula separates the supraspinous from the infraspinous fossa
This anterior arm muscle originates from the coracoid process, inserts on the middle one-third of the medial humerus, and assists with humeral flexion and adduction.
Coracobrachialis
A newborn presents with Erb's palsy after a difficult delivery. Which roots are most commonly involved, and what is the classic arm posture?
C5–C6 (upper trunk); "waiter's tip" posture — arm adducted, internally rotated, elbow extended, forearm pronated
Name the medial and lateral collateral ligament complexes of the elbow, identify which ligament is most commonly injured in throwing athletes ("Tommy John"), and name the band of that ligament most stressed during throwing.
Medial (ulnar) collateral ligament complex (UCL) and lateral (radial) collateral ligament complex (LCL/LUCL); the UCL is the "Tommy John" ligament; the anterior band of the UCL is most stressed during throwing.
A patient sustains a fracture at the anatomical neck of the humerus. What major complication are you most concerned about, and why?
Avascular necrosis (AVN) of the humeral head — the anatomical neck is just distal to the articular cartilage, and disruption of the anterior and posterior circumflex humeral arteries can compromise blood supply to the head