12 Questions
What is the attachment point of the deltoid muscle on the humerus?
Deltoid tuberosity of humerus
Which nerve supplies the deltoid muscle?
Axillary nerve
What is the action of the anterior deltoid?
Shoulder flexion and internal rotation
Which artery is responsible for supplying blood to the deltoid muscle?
All of the above
What is the action of the medial deltoid?
Shoulder abduction
What is the primary function of the supraspinatus muscle?
Initiation of abduction
Which muscle is responsible for pure abduction of the shoulder?
Deltoid
What is the distal attachment point of the supraspinatus muscle?
Superior facet of greater tubercle of Humerus
Which nerve supplies the teres minor muscle?
Axillary Nerve
What is the proximal attachment point of the infraspinatus muscle?
Infraspinous fossa of Scapula
Which muscle is responsible for external rotation and shoulder extension?
Posterior deltoid
What is the blood supply of the infraspinatus muscle?
Circumflex Scapular Artery
Study Notes
Deltoid Muscle
- Proximal attachments include the lateral 1/3 of the clavicle, acromium, and spine of scapula
Attachments
- Distal attachment is at the deltoid tuberosity of the humerus
Blood Supply
- Supplied by the posterior circumflex humeral artery
- Also receives blood from the deltoid branch of the thoracoacromial artery
Nerve Supply
- Innervated by the axillary nerve
Actions
- Anterior fibers perform shoulder flexion and internal rotation
- Medial fibers perform pure abduction
- Posterior fibers perform shoulder extension and external rotation
Deltoid Muscle
- Proximal attachment: Lateral 1/3 clavicle, Acromium, and Spine of Scapula
- Distal attachment: Deltoid tuberosity of Humerus
- Blood supply: Posterior Circumflex Humeral Artery and Deltoid branch of Thoracoacromial Artery
- Nerve supply: Axillary Nerve
- Actions: Anteriorly - Shoulder Flexion/Internal Rotation, Medially - Pure ABDuction, Posteriorly - Shoulder extension/External Rotation
Supraspinatus Muscle
- Proximal attachment: Supraspinous fossa of Scapula
- Distal attachment: Superior facet of greater tubercle of Humerus
- Blood supply: Circumflex Scapular Artery
- Nerve supply: Suprascapular Nerve
- Actions: Assists Deltoid in initial 20° of abduction, "Initiator of Abduction", and External Rotation
Infraspinatus Muscle
- Proximal attachment: Infraspinous fossa of Scapula
- Distal attachment: Middle facet of greater tubercle of Humerus
- Blood supply: Circumflex Scapular Artery
- Nerve supply: Suprascapular Nerve
- Action: External Rotation
Teres Minor Muscle
- Proximal attachment: Middle part of lateral border of Scapula
- Distal attachment: Inferior facet of greater tubercle of Humerus
- Blood supply: Subscapular/Circumflex Scapular Artery
- Nerve supply: Axillary Nerve
- Action: External Rotation
Quiz about the deltoid muscle, covering its attachments, blood supply, nerve supply, and actions.
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