pelvic与pelvis如何区分

There are a variety of indications for epidural steroid injections. These injections may benefit patients with radiculopathy, degenerative disc disease, disc herniation, refractory discogenic pain, spinal nerve compression, spinal nerve root irritation or inflammation, foraminal or central canal stenosis, vertebral compression fractures, herpes zoster/postherpetic neuralgia, post laminectomy syndrome, complex regional pain syndrome, peripheral neuropathy, phantom limb, or cancer-related pain. Additionally, thoracic epidural steroid injections may benefit patients with angina, pancreatic disease, and incisional neuralgia after thoracotomy or breast surgery. Caudal epidurals may benefit patients with sacral or coccygeal neuralgia, interstitial neuritis, as well as pelvic, rectal, perineal, penile, or testicular pain.

硬膜外类固醇注射有多种适应证。硬膜外类固醇注射可能有助于治疗神经根病、椎间盘退变性疾病、椎间盘突出症、顽固性盘源性疼痛、脊神经受压、脊神经根刺激或炎症、椎间孔或中央管狭窄、椎体压缩性骨折、带状疱疹和带状疱疹后遗神经痛、椎板切除术后综合征、复杂区域疼痛综合征、周围神经病变、幻肢痛、癌症相关疼痛。此外，胸椎硬膜外类固醇注射还有助于治疗心绞痛、胰腺疾病、开胸或乳房手术后的切口神经痛。骶管硬膜外注射可使骶尾神经痛、间质性神经炎，以及骨盆、直肠、会阴、阴茎或睾丸疼痛的患者受益。

pelvic应该是骨盆的意思，没有盆腔的意思。

pelvis有骨盆，也有骨盆腔的意思

我想知道如何区分，ic与is 的意思区分？谢谢