Question
| A. | Latissimus dorsi |
| B. |
Teres major |
| C. |
Pectoralis major |
| D. |
Deltoid |
|
Correct Answer � A Explanation |
 |
Ans. is ‘a’ i.e., Latissimus dorsi
The intertubercular sulcus (bicipital groove) of the humerus is an important anatomical site on the anterior surface of the proximal humerus. It serves as the insertion point for three key muscles that act on the shoulder joint:
-
Pectoralis major → lateral lip
-
Teres major → medial lip
-
Latissimus dorsi → floor of the sulcus
This layout is often remembered by the mnemonic:
“Lady between two Majors“
Lady = Latissimus dorsi (in the floor)
Between = between
Two Majors = Pectoralis major (lateral lip)and Teres major (medial lip)
The shaft of the humerus is cylindrical in the upper half and triangular in cross-section in the lower half. The upper part has an anterior intertubercular sulcus (bicipital groove). The bicipital groove contains the long head of the biceps with its synovial sheath and an ascending branch of the anterior circumflex humeral artery.
The middle third of the posterior surface of the shaft of the humerus has a spiral groove (radial groove) which contains the radial nerve and profunda brachii vessels.
Attachment to shafts is ‑
* Insertions of pectoralis major (on lateral lip of bicipital groove), latissimus dorsi (on floor of bicipital groove), teres major (on deltoid tuberosity), and coracobrachialis (medially on mid shaft).
* Origin of brachialis (anterior surface); Lateral and medial head of triceps (posterior surface); pronator teres (from medial supracondylar ridge); brachioradialis (from lateral supracondylar ridge) and ECRL (from lateral supracondylar ridge).
