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Questions and Answers
What is the primary function of the external obliques when they contract together?
Where does the internal obliques attach superiorly?
Which muscle is responsible for compressing the abdomen?
Which of the following describes the attachments of the rectus abdominis?
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What role does the quadratus lumborum play in spinal movement?
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What is the main feature of the linea alba?
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Which muscle primarily functions as a scapular adductor?
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What is the role of the teres minor muscle?
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Which of the following is a primary flexor of the forearm?
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What connects the external obliques to the inguinal region?
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Study Notes
Abdominal Muscles
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External Obliques: Superficial, extend inferiorly and medially, connect to serratus anterior, superior attachment at ribs 5-12, inferior attachment at linea alba and iliac crest.
- Function: Compress abdomen and flex vertebrae together, flex and rotate vertebrae singly.
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Internal Obliques: Superior attachment at cartilage of ribs 7-10 and thoracolumbar fascia, inferior attachment at iliac crest, linea alba, and inguinal ligament.
- Function: Same as external obliques.
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Transverse Abdominis: Superior attachment at iliac crest, inguinal ligament, cartilage of ribs 5-10, and lumbar fascia, inferior attachment at xiphoid process, linea alba, and pubis.
- Function: Compress abdomen.
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Rectus Abdominis: Interrupted by 3-4 tendinous intersections fused with the rectus sheath (formed from aponeuroses of transverse and obliques), superior attachment at cartilage of ribs 5-7 and xiphoid process, inferior attachment at pubic crest and symphysis.
- Function: Rotates vertebrae and flexes abdomen (childbirth, urinating).
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Quadratus Lumborum: Forms part of the posterior abdominal wall, superior attachment at inferior parts of rib 12 and L1-4, inferior attachment at iliac crest and iliolumbar ligament.
- Function: Pulls 12th ribs back together, flexes, rotates vertebrae, and elevates the hip singly.
- Linea Alba: Forms from rectus sheaths, extends from xiphoid to pubic symphysis, stretches during pregnancy.
- Inguinal Ligament: Formed from the inferior free border of external obliques, extends from anterior iliac spine to pubic tubercle, its medial end creates the inguinal ring, and the inguinal canal is where the spermatic cord and nerve cord pass through.
Scapular Muscles
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Trapezius: Proximal attachment at the occipital bone, nuchal ligament (C7-T12), distal attachment at acromion and clavicle.
- Function: All scapula movements (most superficial).
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Levator Scapulae: Proximal attachment at C1-4, distal attachment at superior border of scapula.
- Function: Elevates and rotates scapula downward, flexes neck.
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Rhomboid Major: Proximal attachment at T2-5, distal attachment at border of scapula.
- Function: Adducts, rotates, and stabilizes scapula.
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Rhomboid Minor: Proximal attachment at C7-T1, distal attachment at border of scapula.
- Function: Same as rhomboid major.
Shoulder Muscles
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Deltoid: Superior attachment at the scapula, inferior attachment at the deltoid tuberosity.
- Function: Frequent site of intramuscular injections.
- Subscapularis: Superior attachment at the scapula, inferior attachment at lesser tubercle.
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Supraspinatus: Superior attachment at supraspinous fossa, inferior attachment at greater tubercle.
- Function: Helps deltoid.
- Infraspinatus: Superior attachment at infraspinous fossa, inferior attachment at greater tubercle.
- Teres Major: Superior attachment at inferior angle, inferior attachment at intertubercular sulcus.
- Teres Minor: Superior attachment at inferior border of scapula, inferior attachment at greater tubercle.
- Latissimus Dorsi: Superior attachment at T7-L5, crests of ilium and sacrum, and ribs 9-12, inferior attachment at intertubercular sulcus.
Pectoral Muscles
- Pectoralis Major: Superior attachment at clavicle, ribs 1-7, and sternum, inferior attachment at intertubercular sulcus.
- Pectoralis Minor: Superior attachment at ribs 2-5, inferior attachment at coracoid process.
Other Shoulder Muscles
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Serratus Anterior: Superior attachment at ribs 1-9, inferior attachment at scapula.
- Function: Antagonist of rhomboids.
- Coracobrachialis: Superior attachment at coracoid process, inferior attachment at mid shaft of humerus.
- Biceps Brachii: Long head: supraglenoid cavity, short head: coracoid process, both meet together to form bicep aponeurosis where it splits to muscles of the forearm at the radial tuberosity.
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Brachialis: Superior attachment at humerus, inferior attachment at tuberosity and coracoid process of ulna.
- Function: Strongest flexor.
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Brachioradialis: Superior attachment at humerus, inferior attachment at styloid process of radius.
- Function: Quick movements.
Elbow Muscles
- Triceps Brachii: Long head: infraglenoid tubercle, lateral head: posterior humerus, medial head: posterior humerus, all meet at the olecranon.
- Anconeus: Superior attachment at lateral epicondyle, inferior attachment at olecranon.
Forearm Muscles
- Pronator Teres: Superior attachment at medial epicondyle of humerus and coronoid process of ulna, inferior attachment at radius.
- Pronator Quadratus: Superior attachment at ulna, inferior attachment at radius (distal ends).
- Supinator: Superior attachment at lateral epicondyle of humerus, inferior attachment at radius.
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Description
This quiz covers the anatomy and functions of abdominal muscles, including the external and internal obliques, transverse abdominis, and rectus abdominis. Test your knowledge on their attachments and roles in the body. Perfect for anatomy students and enthusiasts.
