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Muscles of Respiration + Abdomen Cheat Sheet (DRAFT) by

Muscles of respiration and abdomen

This is a draft cheat sheet. It is a work in progress and is not finished yet.


Orig­in: manubrium of sternu­m/c­lavicle
Inse­rti­on: Xiphoid process, pectoral fascia, lower ribs, costal cartilages or rectus sheath
Nerve: Medial and Lateral Pectoral Nerves C6-T1
Acti­on: Unknown


- Satellite Trps can develop from SCM
- Can mimic Chosto­cho­ndr­iti­s/T­ietzes
- Lower SCM + Pec major needs to be treated with Sternalis

External Interc­ostals

Orig­in: Tubercles of the ribs, posterior fibres of superior costot­ran­sverse ligaments, external interc­ostal membrane, lower border of one rib
Inse­rti­on: Upper border of the rib below, free ends of the costal carilages
Nerve: Adjacent Interc­ostal nerves
Acti­on: Stiffens chest wall - prevents parado­xical motion during descent of the diaphragm in inspir­ation

External Interc­ostals - Palpation

- Just inferior to pec major on rib cage
- Roll finger across rib space
- Pt takes several slow deep breaths

Internal Interc­ostals

Orig­in: Rib - Superior Border
Inse­rti­on: Rib - Inferior border
Nerve: Adjacent interc­ostal nerves
Acti­on: Holds ribs steady during expiration
- Antagonist - External interc­ostal


- Interc­ostals have a postural role
- Tx rotation can be limited by TrPs in interc­ostals
- Raising arm above the head will be difficult in patients with interc­ostal TrPs due to pain
- Interc­ostal TrPs may narrow the interc­ostal space enough for this to be palpated


Ster­nal: Back of the xiphoid process
Cost­al: Internal surfaces of the lower 6 costal cartil­lages, interd­igi­tations with Trasnverse Abdominis
Lumb­ar: Medial and lateral arcuate ligaments
Nerve: Phrenic Nerve C3-5
Acti­on: Respir­ation

Diaphragm palpation

Side lying/­supine with knees bent and bolstered
Curl fingers on underside of ribs as patient exhales

External Obliques

Orig­in: Ribs 5-12
Inse­rti­on: Xiphoid Process, outer lip iliac crest, pubic crest, pubic tubercle, linea alba, inguinal ligament , ASIS
Nerve: Terminal Branches of lower five interc­ostal nerves + subcostal nerve from ventral rami of lower 6 tx spinal nerves
Acti­on: Mainte­nance of abdominal tone, increasing intra-­abd­ominal pressure and lateral flexion of the trunk against resistance

External Obliques - Palpation


- Can be incons­istent

Internal Obliques

Orig­in: Inguinal Ligament, iliac crest and lumbod­orsal fascia
Inse­rti­on: Linea alba, Pectinal line of pubis, Ribs 10-12
Nerve: Thorac­oab­dominal (T7-T11), Subcostal (T12), Iliohy­pog­astric (L1), Ilioin­guninal (L1)
Bila­ter­al: Compresses abdomen (expir­ation)
Unil­ate­ral: Ipsila­teral Trunk Rotation


Orig­in: Pubic Symphysis and Pubic Crest
Inse­rti­on: Linea Alba
Nerve: Subcostal Nerve (T12)
Acti­ons: Tenses the Linea Alba


Rectus Abdominis

Orig­in: Crest of Pubis
Inse­rti­on: Costal Cartilages of ribs 5-7 , Xiphoid process of sternum
Nerve: Thorac­oab­dominal nerves (T7-T11), Subcostal (T12)
Acti­on: Flexion of Lumbar spine

Rectus Abdominis - Palpation


- Lower Rectus and upper rectus can overlap
- Lower Rectus TrPs can increase pain in menstr­ation

Transverse abdominis

Orig­in: Iliac Crest, Inguinal ligament, thorac­olumbar fascia and costal cartilages 7-12
Inse­rti­on: Xiphoid Process, linea alba, pubic crest, pecten pubis
Nerve: Thorac­oab­dominal nerve (T6-T11), Subcostal (T12), iliohy­pog­astric nerve (L1), Ilioin­guinal nerve (L1)
Acti­on: Compresses abdominal contents


Abdominal Pain of Myofascial Origin (APoMO)

Visceral Disease
Acute Direct Trauma to Abdomen
Chronic Trauma from Occupa­tional or Postural Stresses
Parado­xical Breathing
Trauma­/sc­arring from injury
Structural Problems (LL inequa­lity, scoliosis)
Overuse of abdominals
TrPs: Abdominal muscul­ature, QL, Ilioco­stalis Thoracis, Multif­idus, Iliosp­soas, Adductors of the thigh
- Can refer pain to the genita­ls/­gro­in/back (entra­pment of the anterior branch of the spinal nerve)
Mana­gem­ent: Rule out visceral causes, fascial release of scars, Home stretch (1-2 reps for 10 seconds), allow stomach to sag and take a deep breath, moist heat, self massage, diaphr­agmatic breathing

Exercise for APoMO