A&P

Digastirc

• Origin: Mastoid process (posterior belly)

• Insertion: Mandible near midline (anterior belly), hyoid bone

• Nerve: Posterior belly—facial nerve; anterior belly—mandibular division of trigeminal nerve

• Action: Depresses and retracts mandible; elevates hyoid bone

Geniohyoid

• Origin: Mental protuberance of mandible

• Insertion: Body of hyoid bone

• Nerve: Fibers of C1 and C2 via hypoglossal nerve

• Action: Protracts hyoid bone; depresses mandible

Mylohyoid

• Origin: Body of mandible

• Insertion: Hyoid bone

• Nerve: Mandibular division of trigeminal nerve

• Action: Elevates floor of mouth and tongue; depresses mandible when hyoid bone is fixed

Stylohyoid

• Origin: Styloid process

• Insertion: Hyoid bone

• Nerve: Facial nerve

• Action: Elevates hyoid bone

Omohyoid

• Origin: Superior border of scapula

• Insertion: Hyoid bone

• Nerve: Upper cervical nerves through ansa cervicalis

• Action: Depresses hyoid bone; stabilizes hyoid bone during mouth opening

Sternohyoid

• Origin: Manubrium and first costal cartilage

• Insertion: Hyoid bone

• Nerve: Upper cervical nerves through ansa cervicalis

• Action: Depresses hyoid bone; stabilizes hyoid bone during mouth opening

Thyrohyoid

• Origin: Thyroid cartilage

• Insertion: Hyoid bone

• Nerve: Upper cervical nerves, traveling with hypoglossal nerve

• Action: Depresses hyoid bone and elevates thyroid cartilage of larynx; stabilizes hyoid bone during mouth opening

Sternothyroid

• Origin: Manubrium and first or second costal cartilage

• Insertion: Thyroid cartilage

• Nerve: Upper cervical nerves through ansa cervicalis

• Action: Depresses larynx; stabilizes hyoid bone during mouth opening

Sternocleidomastoid

• Origin: Manubrium and medial clavicle

• Insertion: Mastoid process and superior nuchal line

• Nerve: Accessory nerve (cranial nerve XI)

• Action: Single contraction: laterally flexes head/neck to same side and rotates head/neck to opposite side. Bilateral contraction: flexes neck.

Scalene Muscles

• Origin: C2–C6 vertebrae

• Insertion: First and second ribs

• Nerve: Cervical and brachial plexuses

• Action: Flexes, laterally flexes, and rotates neck

• Anterior: elevation of rib 1; lateral flexion and rotation of neck

• Middle: elevation of rib 1; lateral flexion of neck

• Posterior: elevation of rib 2; lateral flexion of neck

Longissimus Capitis

• Origin: Upper thoracic and lower cervical vertebrae

• Insertion: Mastoid process

• Nerve: Dorsal rami of cervical nerves

• Action: Extends, rotates, and laterally flexes neck

Oblique Capitis Superior

• Origin: Atlas

• Insertion: Occipital bone (inferior nuchal line)

• Nerve: Dorsal ramus of C1

• Action: Extends and laterally flexes neck; turns head

Rectus Capitis Posterior

• Origin: Axis, atlas

• Insertion: Occipital bone

• Nerve: Dorsal ramus of C1

• Action: Extends and rotates neck; turns head

Semispinalis Capitis

• Origin: C4–T6 vertebrae

• Insertion: Occipital bone

• Nerve: Dorsal rami of cervical nerves

• Action: Extends and rotates neck

Splenius Capitis

• Origin: C4–T6 vertebrae

• Insertion: Superior nuchal line and mastoid process

• Nerve: Dorsal rami of cervical nerves

• Action: Extends, rotates, and laterally flexes neck

Trapezius

• Origin: Occipital protuberance, nuchal ligament, spinous processes of C7–T12

• Insertion: Clavicle, acromion process, and scapular spine

• Nerve: Accessory nerve (cranial nerve XI)

• Action: Extends and laterally flexes neck

• Superior fibers: elevation of scapula; superior rotation of scapula (glenoid cavity directed superiorly)

• Middle fibers: retraction (adduction) of scapula

• Inferior fibers: depression of scapula

Origin:

• Occipital bone (superior nuchal line)

• Nuchal ligament

• Vertebra prominens (spinous process of C7 vertebra)

• Spinous processes of T1-12 vertebrae

Insertion:

• Clavicle (lateral)

• Scapula (spine and acromion)

Innervation:

• Accessory nerve (CN XI)

Frontal Bone

Greater wing of sphenoid bone

Inferior or middle nasal conchae

Infraorbital foramen

Maxilla

Mental foraemen

Nasal bones

Perpendicular plate of ethmoid

Sphenoid bon

Zygomatic bone

Vomer

Condylar process of mandible

Coronid process of mandible

External acoustic meatus

Mastoid process

Parietal bone

Pterion

Ramus of mandible

Squamous part of temporal bone

Styloid process of temporal bone

Temporal bones

Temporal process of zygomatic bone

Temporal process of zygomatic bone

Zygomatic arch

Zygomatic process of temporal bone

Buccinator m.

Action:

• Compression of cheek (e.g., inflating a balloon; playing a wind musical instrument)

Origin:

• Pterygomandibular raphe

• Maxilla (lateral aspect)

• Mandible (lateral body)

Nasalis m.

Action:

• Widen naris (flares nostril)

Origin:

• Maxilla

Insertion:

• Alar cartilage (of nose)

Innervation:

• Facial nerve (CN VII)

Orbicularis Oculi m.

Action:

• Closes eyelids (blink/wink)

Origin:

• Frontal bone

• Maxilla

Insertion:

• Fibers blend at lateral side of orbit

Innervation:

• Facial nerve (CN VII)

Orbicularis oris m.

Action:

• Closes lips

• Protrudes lips (pucker)

Origin:

• Skin around mouth

• Mandible (midline)

• Maxilla (midline)

Insertion:

• Lips

• Interdigitation with fibers from opposite side

Innervation:

• Facial nerve (CN VII)

Platysma m.

Action:

• Elevates and creases skin of neck (e.g., expression of "horror")

• Depression of lower lip and angle of mouth

Origin:

• Fascia of upper thorax and lower neck

Insertion:

• Mandible (lower border)

• Skin and fascia of lower face

• Blends with muscles of lower lip and angle of mouth

Innervation:

• Facial nerve (CN VII)

Scalene mm.

Action:

• Anterior: elevation of rib 1; lateral flexion and rotation of neck

• Middle: elevation of rib 1; lateral flexion of neck

• Posterior: elevation of rib 2; lateral flexion of neck

Origin:

• Transverse processes of C3-7 vertebrae

Insertion:

• Anterior: rib 1

• Middle: rib 1

• Posterior: rib 2

Innervation:

• Ventral rami of cervical spinal nerves

Comment:

• Neck movements produced when rib is fixed

• Important accessory muscles of respiration

• Important anatomical relationship: roots of brachial plexus found between anterior and middle scalene muscles

Zygomaticus Major m.

Action:

• Elevation of corner of mouth (smile)

Origin:

• Zygomatic bone

Insertion:

• Blends with muscles at angle of mouth

Innervation:

• Facial nerve (CN VII)

Zygomaticus minor m.

Action:

• Elevation of upper lip

• Produces nasolabial furrow

Origin:

• Zygomatic bone

Insertion:

• Blends with orbicularis oris muscle

Innervation:

• Facial nerve (CN VII)

Deprssor anguli oris m.

Action:

• Depression of angle of mouth (grimace)

Origin:

• Mandible (body)

Insertion:

• Blends with muscles at angle of mouth

Innervation:

• Facial nerve (CN VII)

Depressor labii inferioris m.

Action:

• Depression of lower lip (pout)

Origin:

• Mandible (body)

Insertion:

• Blends with muscles of lower lip

Innervation:

• Facial nerve (CN VII)

Frontalis m.

Action:

• Elevation of eyebrows

• Creases skin of forehead

• Moves scalp forward (works with occipitalis muscle)

Origin:

• Epicranial aponeurosis

Insertion:

• Skin of eyebrow and forehead

• Blends with orbicularis oculi muscle

Innervation:

• Facial nerve (CN VII)

Comment:

• Part of occipitofrontalis muscle

Genioglossus m.

Action:

• Protraction of tongue ("sticking tongue out")

Origin:

• Mandible (mental tubercle)

Insertion:

• Blends with musculature of tongue

Innervation:

• Hypoglossal nerve (CN XII)

Hyoglossus m.

Action:

• Depression of tongue

Origin:

• Hyoid bone

Insertion:

• Blends with musculature of tongue

Innervation:

• Hypoglossal nerve (CN XII)

Inferior oblique m.

Action:

• Elevation of eyeball (e.g., looking upward)

• Abduction of eyeball (e.g., looking outward)

• Lateral rotation of eyeball

Origin:

• Maxilla (anterior medial floor of orbit)

Insertion:

• Sclera (inferior lateral)

Innervation:

• Oculomotor nerve (CN III)

Inferior recuts m.

Action:

• Depression of eyeball (e.g., looking downward)

• Adduction of eyeball (e.g., looking inward)

• Lateral rotation of eyeball

Origin:

• Common tendinous ring (at posterior of orbit)

Insertion:

• Sclera (inferior surface of eyeball)

Innervation:

• Oculomotor nerve (CN III)

Comment:

• Common tendinous ring is a fibrous band inside the orbit that surrounds optic canal and part of superior orbital fissure

Lateral rectus m.

Action:

• Abduction of eyeball (e.g., looking outward)

Origin:

• Common tendinous ring (at posterior of orbit)

Insertion:

• Sclera (lateral surface of eyeball)

Innervation:

• Abducens nerve (CN VI)

Levator anguli oris m.

Action:

• Elevation of angle of mouth (smile)

Origin:

• Maxilla

Insertion:

• Blends with muscles at angle of mouth

Innervation:

• Facial nerve (CN VII)

Levator labii superioris m.

Action:

• Elevation of upper lip (sneer)

Origin:

• Maxilla

• Zygomatic bone

Insertion:

• Blends with muscles of upper lip

Innervation:

• Facial nerve (CN VII)

Levator palpebrae superioris m.

Action:

• Elevation of upper eyelid

Origin:

• Sphenoid bone (superior to common tendinous ring)

Insertion:

• Upper eyelid

Innervation:

• Oculomotor nerve (CN III)

Masseter m.

Action:

• Elevation of mandible (e.g., closing mouth)

• Protraction of mandible

Origin:

• Zygomatic arch

Insertion:

• Mandible (external surface of angle and ramus)

Innervation:

• Trigeminal nerve (mandibular division - CN V3)

Comment:

• Important muscle for mastication (chewing)

Medial pterygoid m.

Action:

• Elevation of mandible (e.g., closing mouth)

• Protraction of mandible

• Side-to-side movement of mandible (e.g., chewing)

Origin:

• Sphenoid bone (lateral pterygoid plate)

Insertion:

• Mandible (medial surface of angle and ramus)

Innervation:

• Trigeminal nerve (mandibular division - CN V3)

medial rectus m

Action:

• Adduction of eyeball (e.g., looking inward)

Origin:

• Common tendinous ring (at posterior of orbit)

Insertion:

• Sclera (medial surface of eyeball)

Innervation:

• Oculomotor nerve (CN III)

Comment:

• Common tendinous ring is a fibrous band inside the orbit that surrounds optic canal and part of superior orbital fissure

Occipitalis

Action:

• Elevation of eyebrows

• Creases skin of forehead

• Moves scalp backward (works with frontalis muscle)

Origin:

• Occipital bone (superior nuchal line)

Insertion:

• Epicranial aponeurosis

Innervation:

• Facial nerve (CN VII)

Comment:

• Part of occipitofrontalis muscle

occipitalsfrontalis m.

Action:

• Elevation of eyebrows

• Creases skin of forehead

• Moves scalp backward and forward

Origin:

• Occipitalis: occipital bone (superior nuchal line)

• Frontalis: skin of eyebrow and forehead (blends with orbicularis oculi muscle)

Insertion:

• Epicranial aponeurosis

Innervation:

• Facial nerve (CN VII)

pharyngeal constrictor mm.

Action:

• Produces a wave of contraction (peristalsis) during swallowing

Origin:

• Pterygomandibular raphe (superior constrictor)

• Hyoid bone (middle constrictor)

• Thyroid and cricoid cartilages of larynx (inferior constrictor)

Insertion:

• Posterior midline raphe

• Base of skull (superior constrictor)

Innervation:

• Vagus nerve (CN X)

Comment:

• A raphe is a "seam" where two structures meet

Semispinalis capitis m.

Action:

• Unilateral: rotation of head to opposite side

• Bilateral: extension of head and neck

Origin:

• Transverse processes of C7-T6 vertebrae

Insertion:

• Occipital bone

Innervation:

• Cervical spinal nerves (dorsal rami)

Splenius capitis m.

Action:

• Unilateral: rotation of head to same side

• Bilateral: extension of head and neck

Origin:

• Nuchal ligament

• Vertebra prominens (C7 spinous process)

• Spinous processes of T1-3 vertebrae

Insertion:

• Temporal bone (mastoid process)

• Occipital bone (superior nuchal line)

Splenius cervicis m.

Action:

• Unilateral: rotation of head to same side

• Bilateral: extension of head and neck

Origin:

• Spinous processes of T3-6 vertebrae

Insertion:

• Transverse processes of C1-3 vertebrae

Innervation:

• Dorsal rami of C3-5 spinal nerves

Manubrium

Location:

• Sternum

Description:

• Triangular shape

• Superior part of sternum

• Articulates with costal cartilages of ribs 1-2 and clavicles

Comment:

• Provides attachment for sternocleidomastoid and pectoralis major muscles

Which vertebrae make up the cervical vertebra

C1-C7

Which vertebrae make up the thoracic vertebra?

L1 - L12

Which of the ribs are ture ribs?

ribs 1-7

Which of the ribs are false ribs?

8-10

Which vertebrae make up the lumbar vertabra

L1-L5

Inferior articular process of cervical vertebra

Superior articular process of vervical vertebra

Lamina of cervical vertebra

Pedicle of cervical vertebra

Spinous process of the cervical vertebra

Transverse foramen of the cervical vertebra.

Transverse process of the cervical vertebrae

Vertebral foramen of cervical vertebra

posterior arch of the atlas (C1)

Superior articular facet of the atlas (C1)

Dens of the axis (C2)

Pedicle of the axis

Thoracic vertebra

Lumbar vertebra

External abdominal oblique m.

Action:

• Unilateral: rotation of trunk

• Bilateral: flexion of trunk (sit-ups)

• Compression of anterior abdominal wall and viscera (increases intra-abdominal pressure)

Origin:

• Ribs and costal cartilages 5-12

Insertion:

• Linea alba

• Ilium (crest)

Innervation:

• Ventral rami of T8-L1 spinal nerves

Comment:

• Important in "straining" (e.g., lifting, defecation, urination, child-birth)

• Functions in respiration ("abdominal breathing")

• At right angle to internal abdominal oblique (strengthens abdominal wall)

External intercostal m and membrane

Action:

• Muscle of respiration

• Elevation of ribs during inhalation to increase transverse dimensions (anterior-posterior, medial-lateral) of thoracic cavity

Origin:

• Inferior border of rib (ribs 1-11)

Insertion:

• Superior border of rib below (ribs 2-12)

Innervation:

• Intercostal nerves (ventral rami of T1-11 spinal nerves)

Comment:

• External intercostal muscle continuous with external intercostal membrane near sternum

• In contemporary medical anatomy books, the origins of external and internal intercostal muscles are referred to as "superior attachments" and described for both muscles as the inferior border of the rib. Similarly, the insertions of these muscles are referred to as "inferior attachments" and described as the superior border of the rib below.

Internal intercostal m.

Action:

• Muscle of respiration

• Depression of ribs during forced exhalation to decrease transverse dimensions (anterior-posterior, medial-lateral) of thoracic cavity

Origin:

• Superior border of rib (ribs 1-11)

Insertion:

• Inferior border of rib above (ribs 2-12)

Innervation:

• Intercostal nerves (ventral rami of T1-11 spinal nerves)

Comment:

• Internal intercostal muscle continuous with internal intercostal membrane lateral to vertebral column

• Muscle fibers run inferoposteriorly

• In contemporary medical anatomy books, the origins of external and internal intercostal muscles are referred to as "superior attachments" and described for both muscles as the inferior border of the rib. Similarly, the insertions of these muscles are referred to as "inferior attachments" and described as the superior border of the rib below.

Latissimus dorsi m.

Action:

• Adduction of arm

• Extension of arm

• Medial rotation of arm

Origin:

• Sacral and lumbar spines via thoracolumbar fascia

• Ilium (iliac crest) via thoracolumbar fascia

• Ribs (lower four)

• Spinous processes of T6-12 vertebrae

• Scapula (inferior angle)

Insertion:

• Humerus (floor of intertubercular sulcus)

Innervation:

• Thoracodorsal nerve

Pectoralis majojr m.

Action:

• Adduction of arm

• Medial rotation of arm

• Clavicular head: flexion of arm

• Sternocostal head: extension of arm (from flexed position)

Origin:

• Clavicular head: clavicle (medial part)

• Sternocostal head: sternum, costal cartilages 1-6, and aponeurosis of external abdominal oblique muscle

Insertion:

• Humerus (lateral lip of intertubercular sulcus)

Innervation:

• Lateral pectoral nerve (C5-7)

• Medial pectoral nerve (C8-T1)

Comment:

• Pectoralis major and minor muscles also known as "pecs"

• Pectoralis major active during forced inspiration

Pectoralis minor m.

Action:

• Stabilizes scapula (holds it against thoracic wall)

• Protraction (abduction) of scapula (assists serratus anterior)

• Lateral rotation of scapula (e.g., depresses the acromion)

Origin:

• Ribs 3-5

Insertion:

• Scapula (coracoid process)

Innervation:

• Medial and lateral pectoral nerves

Comment:

• Pectoralis major and minor muscles also known as "pecs"

• Pectoralis minor active during forced inspiration

Rectus abdominis m.

Action:

• Flexion of trunk (sit-ups)

• Compression of anterior abdominal wall

Origin:

• Pubis (crest and symphysis)

Insertion:

• Sternum (xiphoid process)

• Costal cartilages 5-7

Innervation:

• Ventral rami of T7-12 spinal nerves

Comment:

• Three or four bellies, separated by tendinous intersections

• Encased in fibrous (rectus) sheath

• Important in "straining" (e.g., lifting, defecation, urination, child-birth)

• Functions in respiration ("abdominal breathing")

Serratus anterior m.

Action:

• Protraction (abduction) of scapula

• Superior rotation of scapula (directs glenoid cavity superiorly)

• Stabilizes scapula (holds it against thoracic wall)

Origin:

• Ribs 1-9

Insertion:

• Scapula (medial border)

Innervation:

• Long thoracic nerve

Comment:

• Serratus anterior is a prime mover in all reaching and pushing movements

External abdominal oblique m.

Action:

• Unilateral: rotation of trunk

• Bilateral: flexion of trunk (sit-ups)

• Compression of anterior abdominal wall and viscera (increases intra-abdominal pressure)

Origin:

• Ribs and costal cartilages 5-12

Insertion:

• Linea alba

• Ilium (crest)

Innervation:

• Ventral rami of T8-L1 spinal nerves

Comment:

• Important in "straining" (e.g., lifting, defecation, urination, child-birth)

• Functions in respiration ("abdominal breathing")

• At right angle to internal abdominal oblique (strengthens abdominal wall)

Internal abdominal oblique m.

Action:

• Unilateral: rotation of trunk

• Bilateral: flexion of trunk (sit-ups)

• Compression of anterior abdominal wall and viscera (increases intra-abdominal pressure)

Origin:

• Inguinal ligament

• Ilium (crest)

• Thoracolumbar fascia

Insertion:

• Linea alba

• Costal cartilages 7-10

Innervation:

• Ventral rami of T8-L1 spinal nerves

Comment:

• Important in "straining" (e.g., lifting, defecation, urination, child-birth)

• Functions in respiration ("abdominal breathing")

• At right angle to external abdominal oblique (strengthens abdominal wall)

Rectus abdominis m.

Action:

• Flexion of trunk (sit-ups)

• Compression of anterior abdominal wall

Origin:

• Pubis (crest and symphysis)

Insertion:

• Sternum (xiphoid process)

• Costal cartilages 5-7

Innervation:

• Ventral rami of T7-12 spinal nerves

Comment:

• Three or four bellies, separated by tendinous intersections

• Encased in fibrous (rectus) sheath

• Important in "straining" (e.g., lifting, defecation, urination, child-birth)

• Functions in respiration ("abdominal breathing")