Anatomy of Humerous

 Humerus Introduction.

What is Humerus?

→ Humerus is the largest bone of the upper extremity and it defines the human brachium (arm)

ot proximally articulates with Scapula at the glenoid cavity forming the glenohumeral joint (ball and Socket joint)

distally with radius and ulna at the elbow joint (Hinge joint).

the Humerus provides an attachment site for all the rotator cuff muscles

What are the three Parts of Humerus?

proximal Landmarks of Humerous

1. Head
2. anatomical neck
3. surgical neck
4. greater tuberosity
5. lesser tuberosity
6. intertubercular sulcus

Head

1. it is at the upper end of humorous
2. it faces medially, upwards, and backward
3. it is separated from the greater and lesser tuberosity by the anatomical neck

Greater Tuberosity

• laterally located on the humerus
• it has 2 surfaces the anterior and the posterior
• it serves as the attachment of 3 of the rotator cuff muscles
  • supraspinatus - superior facet
  • infraspinatus - middle facet
  • teres minor - inferior facet

Lesser Tuberosity

• medially located
• it provides attachment for the 4th rotator cuff - the subscapularis

intertubercular sulcus

• it separates the 2 tuberosities as its name implies

• the tendon of the long head of the biceps brachii runs through this groove

• the edges are known as the lips

  • teres major -medially
  • pectoralis major- laterally
  • latissimus dorsi- in between the teres major and pectoralis major .

  the surgical neck

  • The axillary nerve and circumflex humeral Vessels lie against the bone here
  • The surgical neck is the most common site of fracture

  Shaft

  • Site of attachment for various muscles

  • Circular proximally and flat distally

  • Deltoid tuberosity lateral side of the Humoral Shaft - deltoid muscle attaches to it

  • radial groove

    • posteriors Surface of the humerus
    • Parallel to the deltoid tuberosity
    • The radial artery and profunda brachii Iie here
    • Anteriorly
      • coracobrachialis
      • deltoid
      • brachialis
      • brachioradialis
    • Posteriorly
      • the medial and lateral head of heads of the triceps

    The distal part of the Humerus

    1. lateral supraepicondylar ridges
       1. rough
       2. provide site of attachment to forearm extensors
    2. medial supraepicondylar ridges
    3. lateral and medial epicondyle
    4. capitulum
    5. trochlea
    6. coronoid fossa
    7. radila fossa
    8. olecranon fossa

  the proximal head of humerus attaches to the radius and ulna

  • capitulum - head of the radius
  • trochlea - trochlear notch of the ulna