Parts of Humerus
1. Upper end
• Greater tubercle
• Lesser tubercle
• Intertubercular sulcus
2. Lower end
- Articular part
- Non-articular part
• Coronoid fossa
• Radial fossa
• Olecranon fossa
Upper end of Humerus
Smooth and rounded.
Articular surface covered by hyaline cartilage.
There are three types of neck.
1. Anatomical neck
2. Surgical neck
3. Morphological neck
|It is the constriction present at the margin of the rounded head.
|Gives attachment to the Capsular ligament of the shoulder joint.
|Capsular ligament is deficient superiorly for the passage of the tendon of the long head of biceps brachii.
|Capsular ligament extends medially from the anatomical neck to the shaft about 1-2 cm.
|It is the constriction present between the upper end of the shaft and below the greater and lesser tubercle.
|It is related to the axillary nerve and posterior and anterior circumflex humeral vessels.
|It is the weakest part of the humerus where fracture commonly takes place.
|Fractures at this point lead to damage to the axillary nerve and vessel associated with it.
That's why it is surgically important.
|It is the junction between epiphysis and diaphysis.
|It is also the true junction of the head and shaft.
|It is the most lateral part located at the proximal end of the humerus.
|Posterio-superior parts bears three flat impression
|Those flattened impressions give attachment to the supraspinatus, infraspinatus, and teres minor muscle to upper, middle, and lower impression respectively.
|Lie just above the surgical neck.
|Give attachment to the subscapularis muscle.
These are the muscles of rotator cuff
Bicipital groove/ Intertubercular sulcus
|It is a vertical groove between lesser tubercle and greater tubercle.
- Long head of biceps with enclosed synovial sheath
- Ascending branch of anterior circumflex humeral artery.
Gives attachment to the pectoralis major
Gives attachment to the teres major
|Floor of groove
Gives attachment to the Latissimus dorsi
Shaft of Humerus
- Anterior border
- Medial border
- Lateral border
Anterior lateral surface
Anterior medial surface
|It begins from the lateral lip of the bicipital groove and runs anteriorly.
|It continues below the margin of the deltoid tuberosity.
|In the lower half it becomes smooth and rounded.
|It ends in the radial fossa.
|It begins from the medial lip of the bicipital groove and gives continuous with the medial epicondyle.
|Rough area in the middle of this border provides insertion to the coracobrachialis muscle.
|Lower area of this border above the medial epicondyle gives origin to the pronator teres.
|It is indistinct in the upper part but prominent in the lower part where it forms the lateral epicondyle.
|Lower parts of this border gives attachment to the lateral intermuscular septum.
|It is the area between the anterior and lateral border.
|Deltoid tuberosity present in this surface which is V-shaped.
|Deltoid tuberosity is the main characteristics features of this surface.
|It is the area between the anterior and medial border.
|Middle of this border nutrient foramen is present which is directed downward.
|It is the area between the medial and lateral border
|An oblique ridge is present in the upper one-third of this surface that is directed downward and laterally.
|Below the ridge there is the presence of a groove called radial groove which lodges radial nerve and profunda brachii vessels.
|An oblique ridge
Give origin to the lateral head of triceps brachii
|Below the radial groove
Gives origin to the medial head of triceps brachii
Lower end of Humerus
• It is a rounded projection and lies laterally.
• Articulates with head of the radius.
• It is a pully shaped projection lies medially.
• Articulates with the trochlear notch of the ulna.
• Lies above capitulum.
• During the full flexion of the elbow joint, the head of the radius fits into the radial fossa.
• Lies posterior aspect above the trochlea.
• During the full extension of the elbow joint, the olecranon process of the ulna fits into the olecranon fossa.
• It lies above the trochlea.
• During full flexion of the elbow joint, the coronoid process of the ulna fits into coronoid fossa.
Attachment of lower end
|Anterior surface of the medial epicondyle
Give the common origin of the superficial flexor of the forearm
|Anterolateral part of the lateral epicondyle
Give common extensor muscles origin
|Posterior surface of the lateral epicondyle
Gives origin to the anconeus muscle
Relation of the nerve
→ It around the surgical neck
→ It passes through the radial groove
→ It lies behind the medial epicondyle