Muscles of Axial Skeleton

1110

Muscle?

Corrugaor Supercilil

A: Frown (draws eyebrow tg / medially) - creates vertical wrinkles over glabella

In: Facial Nerve (CN VII)

Muscle?

Orbicularis Oculi

A: Blink (Closes Eyelid)

IN: Facial Nerve (CN VII)

Muscle?

Occpitofrontialis (Epicranius)

• Frontallis + Occipitalits = portion connected by - epicranial aponurosis

Muscle?

Frontailis

A: Raises eyebrows (draws scalp anteriorly - creates horizontal wrinkles over forehead)

IN: Facial Nerve (CN VII)

Muscle?

Occipitalis

A: Draws scalp posteriorly

In: FACIAL NERVE

Muscle?

Orbicularis Oris

A: Pucker (protrudes lips ; as in kiss)

IN: Facial Nerve (CN VII)

Muscle?

Zygomaticus Major

A: Smile (Draw angle of mouth laterally / upward)

IN: Facial Nerve (CN VII)

• Dimples are due to bifid (spilt zygomaticus major muscle)

Muscle?

Mentailis

A: Pout (Protrudes lower lip)

IN: Facial Nerve (CN VII)

Muscle?

Platysma

A: Tenes Neck: (Draws angle of mouth downward)

IN: Facial Nerve (CN VII)

Muscle?

Temporails

A: Elevates and retracts the mandible (CLOSES JAW)

IN: Trigeminal Nerve (CN V)

Muscle?

Masseter

A: Elevation of Mandible (closes jaw)

IN: Trigeminal Nerve (CN V)

• muscle has a superficial / deep layer

Muscle?

Lateral Rectus

In: Abducens Nerve (CN VI)

Muscle?

Medial Rectus

IN: Oculomotor Nerve (CN II)

Muscle?

Superior Rectus

IN: Occulomotor Nerve (CN III)

Muscle?

Inferior Rectus

IN: Occulomotor Nerve (CN III)

Muscle?

Inferior Oblique

IN: Occulomotor Nerve (CN III)

Muscle?

Superior Oblique

IN: Trochlear Nerve (CN IV)

Muscle?

Splnius Capitits

O: Lower Half of Ligamentum Nuchae / Spinious Process of C7/T3

I: Occipital Bone of Mastoid Bone of Temporal Bone
A: Uniltaerally: Ipisilatearl side flexion / rotation of head (CEREVICAL IV JOINTS / ATLANTOCCIPITAL JOINTS)

Muscle?

Scalenes

O: Upper-surface of 1st/2nd rib

I: Transverse process of Cerevical Vertebrae
A: Ipsilateral side flexion of neck

• Anterior Scalenes only = acting biltaerally

Muscle?

Longus Colli

O: Anterior Aspect of Vertebral Bodies C5/T3

I: Anterior Aspect of Vertebral bodies upper-cerevical vertebrae
A: Flexion of Neck (Cerevical Intervertebral joints)

Muscle?

Sternoclediomastoid

O: Manubrium of Sternum / Medial 1/3 of Clavicle

I: Mastoid process of Temporal Bone / Nuchal line of Occipital Bone
A: Unilateral contraction: Ipsilateral side flexion / contralateral rotatation of head (cerevical iv / atlantooccipital joints)

IN: Spinal (Acessory nerve) CN XI

Muscle group?

Erector Spinae

• Muscle group (back extensors)

Includes:

Iliocostialis

Longissismus

Spinailis

Muscle?

Iliocostalis

O:

I:

A:

IN:

Muscle?

Longissimus

O:

I:

A:

IN:

Muscle?

Spinailis

O:

I:

A:

IN:

Muscle?

Iliocostalis

O:

I:

A:

IN:

Muscle?

Quadratus Lumborum

O: Posterior Illiac Crest

I: Transverse Processes of lumbar vertebrae / 12th rib

A:

Unilaterally: Ipsilaterally side flexion of trunk (intervertebral joints)

Bilaterally: Extension of trunk (intervertebral joints)

Muscle?

Thoracolumbar Fascia (TLF)

• Large / diamion-shaped fascial sheet > connective tissue - not a muscle

• extends between vertebrae / sacrum / posterior pelvis

• serves as an attachment site for back muscles / helps provide cohorts for such ; important for posture / force trans / respirtation

What is this

Abdominal Muscles

• Four muscles with fibres orientated im diff directions > combined functions ; trunk stabilization / forced expiration

Muscle?

Rectus Abdominis

O: Pubic Crest / Pubic Symphysis

I: Cartilages of rib 5/7 and xiphoid process
A: Flexion of Trunk (IV Joints)

Muscle?

External Oblique

O: Lower 8 ribs

I: Linea Alba (via abdominal aponeruorsis); anterior illiac crest
A: Unilateral: Ipsilateral side flexion / contralateral rotation of trunk (intervertebral joints)

Muscle?

Internal Oblique

A:

Unilateral: Ipsilateral side flexion / rotation of trunk (intervertebral joints)

Bilateral: Flexion of Trunk (IV Joints)

Muscle?

Transverse Abdominis

O: Thoracolumbar Fascia / Cartilage of lower 6 ribs / illiac crest / inguinal ligament

I: Linea Alba (via abodominal aponeurosis)
A: Conpresses abdominopelvic cavity

What structure?

Rectus Sheath

• Fascial covering rectus abdominis

What Structure

Linea Alba

• vertical midline (connective tissue stucture ; connecting left/right abdominal muscles

Muscle?

Tendinous Intersections

• transverse fibrious bands > segment rectus abdominis into compartments - improving mechanical effciency / force transmission

• limits bulging / enhancing structural support under tension

Muscle?

Thoracic Diaphragm

• Diaphragm Muscle

• Dome-shaped muscle that seperates thoacic / abdominal cavitites

• when it contracts / flattens > increases thoracic volume (decreasing pressure) / decreasing abdominal volume (increases pressure) = enables inspiration / contrib to intra-abdominal pressure reg

Muscle?

• Pelvic Diaphragm (Pelvic Floor)

• dome shaped group of muscles that form the inferior boundary (floor) of pelvic cavity

• when contracts - supports abdoinipelvic organs / resists increases in (intra-abdominal pressure reg)

What Ability

Continence

• ability to voluntary control / release urine and feseces = corrdinated pelvic muscle / neural function

Muscle?

Diaphragm

O: Xiphoid Process of Sternum, lower ribs, upper lumbar vertebrae (peripheral attachments)

I: Central tendon extending to L2-L3

A: Inspiration > raising intra-abdominal pressure for venous return, defecation, urination, childbirth / trunk stabilization

IN: Phrenic Nerve

What is involved in flexion of trunk/vertebral column?

• Rectus Abdominis

• External Obliques

• Internal Obliques

What is involved in Side Flexion (Lateal Flexion) > Trunk / Vertebral Column

• Quadratus Lumborum

• External Oblique

• Internal Oblique

• Iliocostalis

What is involved in Rotation of Trunk / Vertebral Column

• External Oblqiue (contralateral rotation)

• Internal Oblique (Ipislateral rotation)

What is involved in Extension of Trunk / Vertebral Column

• Erector Spinae

• Quadtratus Lumborum (biatearlly)

What reigion

Inner Core-Muscle

• Deep / Core / Local Stabilizers > muscles primarily provide segmental spinal stability / control intra-abdominal pressure

• Internal Obliques / Transverse Abdominis / Diaphragm / Pelvic Floor / Deep Paraspinal muscles

What reigion

Outer core-muscles (Global Movers)

• Rectus Abdominis / External Obliques / Erector Spinae / Quadratus Lumborum / Major Hip and Back muscles

• Including Psoas Major / Minor

What pathology?

Bell’s Palsy

• Sudden onset of unilateral facial weaknesss / paralysis

• loss of voluntary motor function > resulting in facial drooping

• Caused by Ipsilateral lower motor neuron lession of facial nerve (CN VII)

• associated with viral inflammation

What pathology?

Diastasis Recti

• Seperation of rectus abdominis along linea alba due to thinning / widening of connective tissue structure under increased intra-abdominal pressure

• most observed in late preg - may occur with cond involvig chornic increased intra-abdominal pres = including abdominal obesity / heavy lifting / vomitting

What pathology?

Abdominal Hernia

• protrusion of abdominal contents (common intestine) thru a weakened/ torn region > of abdominal wall

• present as visible / palpable bulge w discomfort during straining > often asymptomatic

• results = congenital wekaness / surgical insision / trauma / chornically increasd intra-abdominal pressure

• caused by high-load twisting twisting / cutting / springing movemem t involving forceful hip - adduction / trunk rotation leading to chornic shear stress = across pubic reion

What pathology?

Sports Hernia (Athletic Pubaglia)

• injury of soft tissues of lower abdominal wall / groin reigion

• involves: strain / tearing of muscles, tendons, ligaments > near attachment to pubic bone

• (NOT A TRUE HERNIA > no defect to abdominal wall / protrusion or abdominal contents)

What pathology?

Incontience

• Inability to voluntarily control bladder / bowel release due to impaired pelvic floor muscle / function / neural control

What does Bi/Unilateral movement

bilateral movements use both limbs (arms or legs) simultaneously,

unilateral movements isolate one limb at a time

What is Ipsilateral and contralateral?

Ipsilateral - same side of the body

contralateral - opposite sides of the body

Most Superficial (outer abdominal wall)

External Oblique

• Fibre Direction: Inferomedial (downward / toward midline)

Most Middle Layer

Internal Oblique

• Fibre Direction: Superomedial (upward/ toward midline)

Deepest Layer?

Transverse Abdominis

• Fibre Direction: Horizontal (wraps around abdomen like a belt)

Anterior (within rectus sheeth) not part of lateral wall layering

Rectus Andominis

• Vertical Superior - Inferior

Flexion of Trunk / Vertetebral Column

Muscles:

• Rectus Abdominis

• External Oblique (acting; bilaterally)

• Internal Oblique (acting; bilaterally)

Side Flexion (lateral flexion) of trunk/vertebral column

Muscles included:

• Quadratus

• External Oblique

• Internal Oblique

• Iliocostatlis

Rotation of Trunk/Vertebral Column

• External Oblique (contralateral rotation)

• Internal Oblique (Ipsilateral rotation)

Extension of Trunk / Vertebral Column

• Erector Spinae

• Quadratus Lumborum (acting bilaterally)

What is the core?

Group of muscles that surround / encloses spine / abdomen / pelvis at the centre (core) of the body

• Essential for load bal / force trans > most kinetic chains transmit forces thru the trunk to extremitites

(core can be conceptualized > as a muscular box or container > w the abdominals forming the anterior wall / paraspinials / gluteals forming posterior wall) > under relativevly low corpressive loads

Inner-Core muscles are (deep core / local stabilizers)?

• Internal Obliques

• Transverse Abdominis

• Diaphragm

• Pelvic Floor

• Deep Paraspinal Muscles

Outer-Core muscles are (global movers) > prod mvmnt / contrb to larger-scale force gen; (muscles are?

• Rectus Abdominis

• External Obliques

• Erector Spinae

• Quadratus Lumborum

• Major Hip / Back Muscles