39 Questions
What is the floor of the suboccipital triangle?
Posterior atlantooccipital membrane
Which muscle is responsible for rotating the atlas (and therefore the head) to the same side?
Obliquus capitis inferior
Which muscle is responsible for extending the head?
Rectus capitis posterior major
What is the name of the musculotendinous cuff formed by the tendons of the Supraspinatus, Infraspinatus, Teres Minor, and Subscapularis muscles?
Rotator cuff
Which muscle is responsible for laterally bending the head to the same side?
Obliquus capitis superior
What is the clinical importance of the suboccipital triangle?
It contains the vertebral artery and the dorsal rami of C1 (suboccipital nerve).
Which muscle is responsible for retracting and rotating the scapula to tilt the glenoid cavity inferiorly?
Rhomboid major
Which muscle elevates ribs 2-5?
Serratus posterior superior
Which muscle extends, adducts, and medially rotates the humerus?
Latissimus dorsi
The muscle that elevates and rotates the scapula downward to fix it against the thorax is:
Levator scapulae
Which muscle laterally flexes and rotates the head and neck to the same side?
Splenius capitis
Which muscle group is known as the deep intrinsic muscles of the back?
Erector spinae, Semispinalis, Rotatores longi
What is the prime function of the rotator cuff muscles?
Stabilizing the shoulder joint
Which part of the rotator cuff is most commonly torn?
Supraspinatus tendon
What can a torn rotator cuff potentially lead to?
Dislocation of the shoulder joint
Where is the subacromial bursa located?
Between Supraspinatus tendon and acromion
What is a common condition associated with calcium deposits in the Supraspinatus tendon?
Calcific tendonitis
What is the innervation of the Supraspinatus muscle?
Suprascapular nerve
Which of the following statements about myotomes is correct?
A myotome is a group of muscles innervated by a single spinal nerve derived from the same embryological segment
Which of the following is the correct definition of a dermatome?
A dermatome is an area of skin innervated by a single spinal nerve
Which of the following statements best describes the relationship between extrinsic and intrinsic back muscles?
Extrinsic back muscles are superficial, while intrinsic back muscles are deep
Which of the following statements about the rotator cuff is correct?
The rotator cuff is a group of muscles responsible for the rotation of the shoulder joint
Which muscle group is best developed in both the lumbar and cervical regions, but not the thoracic region?
Intertransversarii
What is the primary action of the levator costarum muscles during unilateral contraction?
Elevate the ribs, assisting inspiration
Which muscle group is deep to the semispinalis and arises from the transverse processes, inserting into the spinous processes 2-4 segments above its origin?
Multifidus
During bilateral contraction, which muscle group primarily extends the vertebral column?
Both rotatores breves and rotatores longus
Which muscle group connects the apices of adjacent spinous processes and is best developed in the cervical region?
Interspinales
What is the primary action of the rotatores breves muscles during unilateral contraction?
Rotate the neck and trunk to the opposite side
Match each superficial back muscle to its origin/ insertion
LATISSIMUS DORSI = O: SP T7-T12, thoracolumbar fascia, iliac crest, ribs 10-12/ I: Floor of intertubercular sulcus of humerus LEVATOR SCAPULAE = O: TP C1-C4/ I: Superior angle of scapula RHOMBOID MAJOR = O: SP T2-T5/ I: Medial border of scapula below spine Trapezius = O:Superior nuchal line, external occipital protuberance, ligamentum nuchae, SP C7-T12/ I:Lateral one-third of the clavicle and acromion and spine of scapula
Match each superficial back muscle to its origin/ insertion
SERRATUS POSTERIOR SUPERIOR = O: SP C7-T3/ I: Superior borders of ribs 2-5 lateral to their angles SERRATUS POSTERIOR INFERIOR = O: SP T11-L2/ I:Inferior border of ribs 9-12 lateral to their angles N/A = N/A RHOMBOID MINOR = O:Ligamentum nuchae, SP C7-T1/ I: Medial border of scapula at spine
Match each superficial back muscle to its action
TRAPEZIUS = Elevates scapula, retracts (adducts) scapula, depresses scapula, rotates the scapula upward, stabilizes scapula LATISSIMUS DORSI = Extends, adducts, and medially rotates humerus LEVATOR SCAPULAE = Elevates and rotates scapula downward, fixes scapula against thorax RHOMBOID MAJOR/RHOMBOID MINOR = Retracts and rotates the scapula to tilt the glenoid cavity inferiorly
Match each extrinsic back muscle to its action
SERRATUS POSTERIOR SUPERIOR = Elevates ribs 2-5 SERRATUS POSTERIOR INFERIOR = Depresses ribs 9-12 N/A = N/A N/A = N/A
Match each extrinsic back muscle to its innervation
TRAPEZIUS = Spinal accessory n. (CN XI)/ Ventral rami of C3 and C4 LATISSIMUS DORSI = Thoracodorsal n. (also middle subscapular n. ) LEVATOR SCAPULAE/RHOMBOID MAJOR/RHOMBOID MINOR = Dorsal scapular n. SERRATUS POSTERIOR INFERIOR = Anterior rami T9-T12
Match each intrinsic back muscle to its origin/ insertion
SPLENIUS CERVICIS = O: Spinous processes of T3- T6/ I:TP C1-C4 Erector Spinae (Spinalis, Longissimus, Iliocostalis) Origin = O: Median sacral crest, posterior surface sacrum, SP L and lower T, medial part of iliac crest Erector Spinae (Spinalis, Longissimus, Iliocostalis) = I (Spinalis): SP of T and C; I (Longissimus):Between tubercles and angles of ribs and TP of T and C; I (Iliocostalis):Angles of lower ribs and TP of C SPLENIUS CAPITIS = O: Ligamentum nuchae, SP C7-T4/ I:Mastoid process, lateral one-third of superior nuchal line
Match each intrinsic muscle of the back to its action
SPLENIUS CERVICIS = Unilateral-laterally flexes and rotates the head to same side Bilateral-extends head and neck Erector Spinae (Spinalis, Longissimus, Iliocostalis) = Unilateral-laterally flexes VT to same side Bilateral-extends VT and head, stabilizes VT N/A = N/A SPLENIUS CAPITIS = Unilateral-laterally flexes and rotates the head and neck to same side Bilateral-extends head and neck
Match each intrinsic muscle of the back to its innervation
SPLENIUS CAPITIS = Posterior rami of middle cervical region SPLENIUS CERVICIS = Posterior rami of lower cervical region Erector Spinae (Spinalis, Longissimus, Iliocostalis) = Posterior rami of lower cervical nerves N/A = N/A
Match each suboccipital triangle muscle to its origin/ insertion
RECTUS CAPITIS POSTERIOR MAJOR = O:Spinous process of the axis (C2)/ I:Occipital bone just inferior to the inferior nuchal line Occipital bone just inferior to the inferior nuchal line RECTUS CAPITIS POSTERIOR MINOR = O: Posterior tubercle of the posterior arch of the atlas (C1)/ I: Occipital bone just inferior to the inferior nuchal line and medial to Rectus capitis posterior major OBLIQUUS CAPITIS INFERIOR = O: Spinous process of the axis (C2)/ I:Tip of the transverse process of the atlas (C1) OBLIQUUS CAPITIS SUPERIOR = O:Tip of the transverse process of the atlas (C1)/ I: Occipital bone between the inferior and superior nuchal lines, superficial and superior to the insertion of Rectus capitis posterior major
Match each suboccipital triangle muscle with its action
RECTUS CAPITIS POSTERIOR MINOR = Extends head OBLIQUUS CAPITIS INFERIOR = Rotates atlas (therefore, the head) on the same side OBLIQUUS CAPITIS SUPERIOR = Unilateral Contraction: Laterally bends head to the same side Bilateral Contraction: Extends head RECTUS CAPITIS POSTERIOR MAJOR = Unilateral Contraction: Rotates the head to the ipsilateral side Bilateral Contraction: Extends the head
Match each rotator cuff muscle to its origin/ insertion
SUPRASPINATUS = O: Supraspinous fossa of the scapula/ I:Superior facet of the greater tubercle of the humerus INFRASPINATUS = O: Infraspinous fossa of the scapula/ I:Middle facet of the greater tubercle of the humerus TERES MINOR = O: Lateral border of the scapula/ I: Inferior facet of the greater tubercle of the humerus SUBSCAPULARIS = O: Subscapular fossa/ I: Lesser tubercle of the humerus
Study Notes
Suboccipital Triangle
- Boundaries: Superior (Rectus capitis posterior major), Medially (Rectus capitis posterior major), Superior and Laterally (Obliquus capitis superior), Inferior and Laterally (Obliquus capitis inferior)
- Floor: Posterior atlantooccipital membrane and posterior arch of the atlas (C1)
- Roof: Semispinalis capitis
- Contains: Vertebral artery and dorsal rami of C1 (suboccipital nerve)
Muscles of the Suboccipital Triangle
- Rectus capitis posterior major:
- Origin: Spinous process of the axis (C2)
- Insertion: Occipital bone just inferior to the inferior nuchal line
- Actions: Unilateral contraction: Rotates the head to the ipsilateral side; Bilateral contraction: Extends the head
- Innervation: Dorsal rami of C1 (suboccipital nerve)
- Rectus capitis posterior minor:
- Origin: Posterior tubercle of the posterior arch of the atlas (C1)
- Insertion: Occipital bone just inferior to the inferior nuchal line and medial to Rectus capitis posterior major
- Actions: Extends the head
- Innervation: Dorsal rami of C1 (suboccipital nerve)
- Obliquus capitis inferior:
- Origin: Spinous process of the axis (C2)
- Insertion: Tip of the transverse process of the atlas (C1)
- Actions: Rotates the atlas (therefore, the head) on the same side
- Innervation: Dorsal rami of C1 (suboccipital nerve)
- Obliquus capitis superior:
- Origin: Tip of the transverse process of the atlas (C1)
- Insertion: Occipital bone between the inferior and superior nuchal lines, superficial and superior to the insertion of Rectus capitis posterior major
- Actions: Unilateral contraction: Laterally bends the head to the same side; Bilateral contraction: Extends the head
- Innervation: Dorsal rami of C1 (suboccipital nerve)
Rotator (Musculotendinous) Cuff
- Formed by the tendons of the Supraspinatus, Infraspinatus, Teres Minor, and Subscapularis (SITS) muscles
- Innervation: Ventral rami of C3 and C4
- Function: Stabilizes the shoulder joint and holds the head of the humerus in the glenoid cavity
Intrinsic Muscles of the Back
- Superficial and Intermediate Group:
- Erector Spinae (Spinalis, Longissimus, Iliocostalis)
- Origin: Median sacral crest, posterior surface of the sacrum, and SP of L and lower T
- Insertion: Between tubercles and angles of ribs and TP of T and C
- Actions: Extends, rotates, and stabilizes the vertebral column
- Innervation: Posterior rami of lower cervical nerves
- Spleinus capitis:
- Origin: Ligamentum nuchae, SP C7-T4
- Insertion: Mastoid process, lateral one-third of superior nuchal line
- Actions: Unilateral contraction: Laterally flexes and rotates the head and neck to the same side; Bilateral contraction: Extends the head and neck
- Innervation: Posterior rami of middle cervical region
- Spleinus cervicis:
- Origin: SP C1-C4
- Insertion: TP C1-C4
- Actions: Unilateral contraction: Laterally flexes and rotates the head and neck to the same side; Bilateral contraction: Extends the head and neck
- Innervation: Posterior rami of lower cervical region
- Erector Spinae (Spinalis, Longissimus, Iliocostalis)
- Deep Group:
- Semispinalis:
- Origin: Deep to erector spinae
- Insertion: Semispinalis thoracis, cervicis, capitis
- Actions: Extends and rotates the vertebral column
- Rotatores:
- Long rotators (11 pairs):
- Origin: Transverse processes
- Insertion: Spinous processes two vertebrae above
- Actions: Rotate the vertebral column
- Short rotators (11 pairs):
- Origin: Transverse processes
- Insertion: Spinous processes of adjacent vertebrae
- Actions: Rotate the vertebral column
- Long rotators (11 pairs):
- Multifidus:
- Origin: Transverse processes
- Insertion: Spinous processes 2-4 segments above
- Actions: Unilateral contraction: Rotates the neck and trunk to the opposite side; Bilateral contraction: Extends the vertebral column
- Semispinalis:
Fascia of the Back
- Superficial layer:
- Divided into two layers: a superficial layer and a deep layer
- Deep layer:
- Thoracolumbar fascia
- Found in the thoracic region
Test your knowledge on the learning objectives of the Back & Shoulder Doctor of Podiatric Medicine (DPM) program. Questions cover topics like extrinsic and intrinsic muscles of the back, dermatome, myotome, cutaneous innervation, and more.
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