Question

and the suprem us IUSS... 31. Know the major structures on the major bones (humerus, ulna, radius, Temui, tula (10). 32. What is the difference between the anatomical neck and the surgical neck? 33. What is found in the radial groove? 34. What structures form the elbow? Shoulder? 35. What is the structure involved in the funny bone? Where is it? 36. Where do you find intraosseous membranes? Describe the three locations the una and radius articulate with each other name the joints), 38. Know the camal bones of the wrist Which bone is the largest? Which bone is most commonly fractured due to FOOSH? What is the band that covers these bones? Most commonly dislocated?

Answer 1

Ans.32) The neck lies just below the head of the humerus. There is a portion called the anatomical neck and one called the surgical neck. The anatomical neck is the portion that lies just below the head. As the neck continues along the humerus body, it is called the surgical neck (so named because this is the location of many fractures that require surgery). The difference between these two are mention below:

Anatomical neck:

• The Anatomical Neck (collum anatomicum) is obliquely directed, forming an obtuse angle with the body. It is best marked in the lower half of its circumference; in the upper half it is represented by a narrow groove separating the head from the tubercles.
• It is less frequently fractured.
• It has lesser tuberosity

Surgical neck:

• The surgical neck of the humerus is a constriction below the tubercles of the greater tubercle and lesser tubercle, and above the deltoid tuberosity. It is much more frequently fractured than the anatomical neck of the humerus.
• It is much more frequently fractured than the anatomical neck of the humerus.
• It has greater tuberosity.

Ans. 33) A broad, shallow groove that spirals down the posterior surface of the humerus and marks the route of the radial nerve and the deep brachial artery.

Ans.34) The bones that create the elbow are:

• Humerus: This long bone extends from the shoulder socket and joins the radius and ulna to form the elbow.
• Radius: This forearm bone runs from the elbow to the thumb side of the wrist.
• Ulna: This forearm bone runs from the elbow to the “pinkie” side of the wrist.

The elbow bones are held together primarily by fibrous tissue known as ligaments. The ulnar collateral ligament, or UCL, on the inner side of the joint closest to the body is the primary stabilizer. This thick triangle-shaped band connects the head of the humerus to the heads of the ulna and radius.

Structure of shoulder :

Articulating Surfaces

The shoulder joint is formed by the articulation of the head of the humerus with the glenoid cavity (or fossa) of the scapula. This gives rise to the alternate name for the shoulder joint – the glenohumeral joint.

Like most synovial joints, the articulating surfaces are covered with hyaline cartilage. The head of the humerus is much larger than the glenoid fossa, giving the joint a wide range of movement at the cost of inherent instability. To reduce the disproportion in surfaces, the glenoid fossa is deepened by a fibrocartilage rim, called the glenoid labrum.

Joint Capsule and Bursae

The joint capsule is a fibrous sheath which encloses the structures of the joint.

It extends from the anatomical neck of the humerus to the border or ‘rim’ of the glenoid fossa. The joint capsule is lax, permitting greater mobility (particularly abduction).

The synovial membrane lines the inner surface of the joint capsule, and produces synovial fluid to reduce friction between the articular surfaces.

To reduce friction in the shoulder joint, several synovial bursae are present. A

bursa is a synovial fluid filled sac, which acts as a cushion between tendons and other joint structures.

The bursae that are important clinically are:

• Subacromial – located deep to the deltoid and acromion, and superficial to the supraspinatus tendon and joint capsule. The subacromial bursa reduces friction beneath the deltoid, promoting free motion of the rotator cuff tendons. Subacromial bursitis (i.e. inflammation of the bursa) can be a cause of shoulder pain.
• Subscapular – located between the subscapularis tendon and the scapula. It reduces wear and tear on the tendon during movement at the shoulder joint.

Ligaments

In the shoulder joint, the ligaments play a key role in stabilising the bony structures.

• Glenohumeral ligaments (superior, middle and inferior) – the joint capsule is formed by this group of ligaments connecting the humerus to the glenoid fossa. They are the main source of stability for the shoulder, holding it in place and preventing it from dislocating anteriorly. They act to stabilise the anterior aspect of the joint.
• Coracohumeral ligament – attaches the base of the coracoid process to the greater tubercle of the humerus. It supports the superior part of the joint capsule.
• Transverse humeral ligament – spans the distance between the two tubercles of the humerus. It holds the tendon of the long head of the biceps in the intertubercular groove.]
• Coraco–clavicular ligament – composed of the trapezoid and conoid ligaments and runs from the clavicle to the coracoid process of the scapula. They work alongside the acromioclavicular ligament to maintain the alignment of the clavicle in relation to the scapula. They have significant strength but large forces (e.g. after a high energy fall) can rupture these ligaments as part of an acromio-clavicular joint (ACJ) injury. In severe ACJ injury, the coraco-clavicular ligaments may require surgical repair.

Ans.35) The ulnar nerve is a nerve that runs near the ulna bone. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest in the human body unprotected by muscle or bone, so injury is common. This nerve is directly connected to the little finger, and the adjacent half of the ring finger, innervating the palmar aspect of these fingers, including both front and back of the tips, perhaps as far back as the fingernail beds.

This nerve can cause an electric shock-like sensation by striking the medial epicondyle of the humerus from posteriorly, or inferiorly with the elbow flexed. The ulnar nerve is trapped between the bone and the overlying skin at this point. This is commonly referred to as bumping one's "funny bone".

Location: You get that funny feeling when the ulnar nerve is bumped against the humerus (say: HYOO-muh-rus), the long bone that starts at your elbow and goes up to your shoulder. Tapping your funny bone doesn't do any damage to your elbow, arm, or ulnar nerve.

Ans. 36) Interosseous membrane labeled at bottom center. The interosseous membrane of the forearm (rarely middle or intermediate radioulnar joint) is a fibrous sheet that connects the interosseous margins of the radius and the ulna. It is the main part of the radio-ulnar syndesmosis, a fibrous joint between the two bones.

Ans.37) The distal radioulnar articulation (inferior radioulnar joint) is a joint between the two bones in the forearm; the radius and ulna. It is one of two joints between the radius and ulna, the other being the proximal radioulnar articulation. he radioulnar joints are two locations in which the radius and ulna articulate in the forearm: Proximal radioulnar joint: This is located near the elbow, and is an articulation between the head of the radius, and the radial notch of the ulna.

Ans.38) The scaphoid bone is the largest carpal bones of the proximal row and it lies beneath the anatomical snuff box. Scaphoid fractures often accompany perilunate dislocation. Carpal dislocations can lead to chronic pain and wrist instability. A scaphoid fracture is a break in one of the eight small bones that make up the wrist. It's one of the most common FOOSH injuries.

The flexor retinaculum is a strong, fibrous band that covers the carpal bones on the palmar side of the hand near the wrist. It attaches to the bones near the radius and ulna. On the ulnar side, the flexor retinaculum attaches to the pisiform bone and the hook of the hamate bone.